FAQs

A. The official European tests are now out of date, and produce results that aren’t realistic when compared to how cars are used in the real world. Recent revelations have also shown that it’s possible to exploit the tests, making a car appear far better than it really is. The official tests only produce a pass or fail result. The EQUA Index provides results on a scale for air quality, carbon monoxide and carbon dioxide, so it’s possible to see exactly how a car has fared. Additionally, the EQUA Mpg Index is a measure of fuel economy when driven in a normal way on the road rather than in the laboratory.

A. The current type approval test, required before a car can go on sale, is conducted in a laboratory on the New European Driving Cycle (NEDC). This is a cycle of less than 20 minutes with low average speeds, low rates of acceleration, no gradients and therefore tests the performance of the vehicle with the engine under relatively low load.

Real-world driving typically puts higher loads on the engine, but this remains largely untested. In addition, the official test protocol contains a number of leniencies and grey areas that can be exploited and optimised to achieve low emissions performance.

A. From September 2017 the WLTP replaces the NEDC as the type approval test for cars in Europe, which will lead to the current CO2 and fuel economy figures migrating to this new basis. The NEDC underestimates real-world CO2 emissions by approximately 30% on average, leading to misleading fuel economy labelling.

The WLTP drive cycle contains higher speeds and accelerations than the NEDC, better reflecting real driving. However, the test remains entirely in the laboratory, and does not expose the car to normal traffic flows and on road gradients. As a fixed cycle, it will also be susceptible to manufacturers optimising their vehicles to this test. The WLTP will, nevertheless, be an improvement, but it will only partially close the current gap between official data and reality.

The new WLTP regulations are separate from the new regulations for nitrogen oxides (NOx), Real Driving Emissions (RDE), which are also being introduced in September 2017. Emissions Analytics also tracks vehicle NOx through its EQUA Air Quality Index (EQUA Aq).

A. Emissions Analytics tests between 200 and 400 vehicles each year in Europe. Testing takes place in the United Kingdom and Germany. It is also active in the United States, testing a similar number of vehicles.

A. Vehicle manufactures appreciate the need to have a transparent and realistic test for emissions, and the EQUA Index will help compare cars from different manufacturers. Recent headlines have also damaged the reputation of diesel vehicles per se, and many now consider them ‘dirty’. The EQUA Index will show that many diesel cars are capable of delivering good emissions results in the real world, and the programme should go a long way in helping restore car buyers’ faith.

A. The programme’s target is to publish a car’s rating less than 48 hours after emissions data has been collected, and the EQUA Index aims to post data for between 200-400 vehicles every year. Consumers can sign up for a monthly e-newsletter, which will provide a roundup of the latest results.

A. The programme will endeavour to test all new vehicles as soon as possible, and as requested. Requests can be sent to EQUAAq@emissionsanalytics.com. Car buyers should raise the question of a car’s emissions with franchised dealers.

A. Consumers are becoming more interested in NOx in the same way that they became interested in CO2, as the subject was linked to environmental concerns and vehicle taxation. There is a growing body of research that points to the damaging effects of NOx on public health. This includes leading bodies, including the World Health Organisation and the Royal Society of Physicians. In addition, from 2020 London and potentially other UK cities, are looking to penalise non-Euro-6 vehicles, by charging them to enter Clean Air Zones. As a result of these access restrictions, targeting vehicle NOx emissions will start to have practical and financial effects for the consumer.

A. The relationship between NOx and CO2 is not straightforward, but some NOx reduction systems can increase CO2 and so reduce Mpg. This depends on the type of system used and the set up of the vehicle.

A. Emissions Analytics has now tested a sufficiently large number of cars across different makes, models, fuels, engine sizes and model years so that it is possible to understand the typical effect on Mpg of each individual element. In this way, it is possible to make a good forecast of what the Mpg will be for a model we have not yet tested.

By making these forecasts, a large portion of the market is covered by the EQUA Index, creating a much more powerful tool for comparing cars. In the published results, actual tests (with the higher degree of accuracy) are clearly labelled and distinct from these forecasts.

A. PEMS are used for the regulatory testing of nitrogen oxides in Europe for heavy duty vehicles, and are planned to be used similarly for passenger cars from 2017. The equipment is used more widely by the US Environmental Protection Agency for in-service surveillance testing.

Emissions Analytics has been using PEMS for fuel economy and CO2 measurement since 2011. Vehicle manufacturers are now beginning to embrace the benefits of on-road measurement, for example PSA Peugeot Citroen recently published real-world fuel consumption numbers on a range of its vehicles, in order to advise consumers better on what performance to expect.

The equipment used by Emissions Analytics meets the standards of UN-ECE R-49 and Commission Regulation (EU) No. 582/2011 in the European Union, and 40CFR part 1065 in the United States. Further details of the equipment used can be found at http://www.sensors-inc.com/. The repeatability quoted by the manufacturer for CO2 – and thereby fuel economy – is typically +/-3%. Emissions Analytics calibrates the equipment to known gas concentrations for each test, according to the equipment manufacturer’s recommendation.

A. Tests have been conducted in a wind tunnel on a car before and after the installation of the PEMS equipment to assess the effect on the aerodynamic drag. With careful installation of the equipment, there was no statistically significant effect on the coefficient of drag.

A. Vehicles typically tested within a few months of first registration and have covered between 1,000 and 5,000 miles. This age of vehicle is used because it ensures that the vehicle has been “de-greened” for a period, but has not be exposed to the variables associated with longer-term operation, including service standards and vehicle care more generally.

A. Currently the EQUA Index programme focuses on testing cars when new, where the service history of the vehicle does not affect performance. Having tested for over five years, there is a back catalogue of ratings for vehicles, which are now exclusively available in the second-hand market, although they were tested when new.

A. The test lasts over three-and-a-half hours and takes in repeated urban, rural and motorway elements. The average speeds of these sections are approximately 17.5 mph, 35 mph and 60 mph respectively. Additional sections of the route also test the vehicle in sportier, high-load modes as well as lower-load “eco” modes in order to understand the range of the vehicle’s performance.

A. As many factors as possible are kept constant between tests, including the route, drivers and their driving style. The vehicles are fully warmed up when the test starts. Ambient conditions must fall within parameters that ensure testing is not conducted under extreme high or low temperatures, rain, snow, ice and high winds.

A. Emissions Analytics has developed a tool to “normalise” for variation in traffic flow to the standard level. This uses the intelligence gathered from the second-by-second test data, and has been validated over a large number of tests. This works because of the relatively predicable relationship between the load on the engine and the fuel burned. In cases where congestion is too far from our standard, the test is deemed invalid.

A. The added weight to each vehicle is the same, approximately equal to being half-loaded for an average car. The weights of the driver, passenger, equipment and level of fuel in the tank are taken into account, with additional ballast used to bring the total weight up to the benchmark level.

A. The driving style across the test is kept constant by using a small team of drivers who are all trained to drive in the same way. This is verified for each individual test and a more detailed audit of driving styles is conducted annually. Within each test, different rates of acceleration are used at different points in order to assess the vehicle performance, but this approach is applied consistently between tests.

A. The fuel used is a standard grade petrol or diesel, conforming to EN228 and EN590 regulations respectively. The only variation from this is if the vehicle manufacturer requires the use of a premium grade. If a premium grade is only “recommended”, then the standard grade is used. The fuel is sourced from a single filling station, which remains the same over time. This enables the best balance of using the same fuel that customers can buy in the real world, and consistency over time. With these controls in place, the remaining variability is not material to fuel economy.

A. We aim to test each model where the model year, engine size, fuel type, power, number of driven wheels, transmission or Euro regulatory stage are distinct. We consider vehicles materially similar where the difference is only in body style, number of doors or trim level.

This is more restrictive than the “families” of vehicle defined under the type approval process.

A. Yes, there is a validation programme, which has been designed specifically by Emissions Analytics. This ensures that the cycle overall, and sub-sections of it, meets a number of validity tests, including average speed, acceleration, presence of Diesel Particulate Filter (DPF) regeneration, engine coolant temperature, ambient climatic conditions, and so on. This ensures that there is the greatest consistency possible between different tests of different vehicles on different days.

A. Repeatability and reproducibility are assessed on a number of levels. First, within each test, repeated identical sub-segments must match each other within certain parameters. Second, a sub-sample of vehicles is retested under the same conditions to ensure consistency. Third, all results are compared to Emissions Analytics’ database to ensure a broader consistency with similar models and technology types. Fourth, a sub-sample of models is selected such that different instances of the same models are tested for inter-model consistency.

A. Emissions Analytics is in the process of testing light commercial vehicles with a view to include it them in the EQUA Index. Emissions Analytics already works with fleet operators to help inform on the selection and set-up of commercial vehicles, in order to help reduce fleet NOx emissions. In addition, it’s working with a number of local authorities to help guide when retrofitting emissions reduction technology to older vehicles.

One of the air quality exhaust pollutants regulated in the European Union is NOx (nitrogen oxides). NOx is a term that refers to the combination of nitric oxide (NO) and nitrogen dioxide (NO2). There is no individual vehicle exhaust limit for NO or NO2, only the sum of both